bug#50752: 28.0.50; easy-menu-define lowers the menu-bar key

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: stefan@marxist.se,  shuguang79@qq.com,  50752@debbugs.gnu.org
> Date: Tue, 19 Oct 2021 19:12:20 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > I think we can leave the behavior with raw bytes as it is, and still
> > document this use case as being meant for ASCII conversions, leaving
> > the subtle case of raw bytes ... subtle.
> 
> Yup.
> 
> The following patch seems to do the trick, and should be conservative
> enough for emacs-28, I think.

I wouldn't start such experiments on the release branch.  It's not an
urgent problem.

> +static int
> +ascii_casify_character (bool downcase, int c)
> +{
> +  Lisp_Object cased = CHAR_TABLE_REF (downcase?
> +                                   uniprop_table (Qlowercase) :
> +                                   uniprop_table (Quppercase),
> +                                   c);
> +  return FIXNATP (cased) ? XFIXNAT (cased) : c;
> +}

uniprop_table is somewhat expensive, and is definitely an overkill for
converting pure ASCII characters.  Why not just set/reset the 0x20
bit?